Plasma display and method for producing the same

ABSTRACT

A plasma display device has a first plate and a second plate which face each other with a discharge space therebetween, and a sealing member which is provided between the first and second plates to seal the discharge space at edges of the first and second plates. A plurality of electrodes are formed on the inner major surface of the first or second plate. An electrode diffusion preventive layer is formed in each area where the plurality of electrodes cross over the sealing member, so as to avoid direct contact between the plurality of electrodes and the sealing member. As a result, problems such as breaking of the electrodes can be avoided. This construction is especially effective when the electrodes contain Ag.

TECHNICAL FIELD

The present invention relates to a plasma display device such as aplasma display panel used for display, and a manufacturing method forthe plasma display device. The invention in particular relates toimprovements to a sealing process.

BACKGROUND ART

Plasma display panels (PDPs) are a type of plasma display devices. PDPsenable large-screen slimline displays to be produced relatively easily,and so are receiving attention as the coming generation of displaypanels. Sixty-inch models have already been commercialized.

FIG. 5 is a partially sectional and perspective view showing a mainconstruction of a typical surface discharge AC (alternating current)PDP. In the drawing, the direction z represents the direction along thethickness of the PDP, and the plane xy represents a plane which isparallel with the panel plane of the PDP. As illustrated, the PDP 2 isroughly made up of a front panel 20 and a back panel 26 which arearranged with their major surfaces facing each other.

A front panel glass 21 is a substrate of the front panel 20. A pair ofdisplay electrodes 22 and 23 (an X electrode 22 and a Y electrode 23)are formed on one of the major surfaces of the front panel glass 21 sothat each electrode runs along the direction x. Surface discharge isperformed between these electrodes. The display electrodes 22 and 23 areformed by placing bus lines 221 and 231 made of a mixture of Ag andglass, on top of transparent electrodes 220 and 230 formed from ITO(Indium Tin Oxide) and the like.

A dielectric layer 24 made of a dielectric material is formed at thecenter of the major surface of the front panel glass 21 on which thedisplay electrodes 22 and 23 have been arranged. A protective layer 25having the same size as the dielectric layer 24 is formed on thedielectric layer 24.

A back panel glass 27 is a substrate of the back panel 26. A pluralityof address electrodes 28 are formed in stripes on one of the majorsurfaces of the back panel glass 27 with a predetermined spacing, sothat each electrode runs along the direction y. The address electrodes28 are formed from a mixture of Ag and glass, like the bus lines 221 and231. A dielectric layer 29 made of a dielectric material is formed atthe center of the major surface of the back panel glass 27 so as tocover the address electrodes 28. Barrier ribs 30 are arranged on thedielectric layer 29 at the gaps between the adjacent address electrodes28. Phosphor layers 31-33 corresponding to the colors of red (R), green(G), and blue (B) are applied to the side faces of the adjacent barrierribs 30 and the surface of the dielectric layer 29 between the adjacentbarrier ribs 30.

Such constructed front panel 20 and back panel 26 are positioned so thatthe address electrodes 28 cross over the display electrodes 22 and 23 atright angles. The front panel 20 and the back panel 26 are then sealedat their edges to make the inside airtight. In more detail, frit glassas a sealing member 40 is applied to the edges of the front panel glass21 (more precisely, around the dielectric layer 24) and the edges of theback panel glass 27 (more precisely, around the dielectric layer 29), asshown in a top view of FIG. 6. This sealing member 40 is melted to sealthe panels 20 and 26. Here, the edges 211 and 212 of the front panelglass 21 and the edges 271 and 272 of the back panel glass 27 areoutlets for respectively connecting the display electrodes 22 and 23 andthe address electrodes 28 to outside drive circuits (not illustrated).

Note that in FIG. 6 the number of display electrodes 22 and 23 and thenumber of address electrodes 28 are fewer than in actual PDPs forpurposes of illustration. The electrodes are indicated by solid lines.Also, the positions of the sealing member 40 and dielectric layer 24 areindicated by solid lines.

A discharge gas (an enclosed gas) including Xe is introduced between thefront panel 20 and the back panel 26 which are sealed together, at apredetermined pressure (typically about 40 kPa-66.5 kPa).

As a result, the spaces which are separated by the dielectric layer 24,the phosphor layers 31-33, and the adjacent barrier ribs 30 between thefront panel 20 and the back panel 26 become discharge spaces 38. Also,the areas at which the pairs of adjacent display electrodes 22 and 23cross over the address electrodes 28 with the discharge spaces 38 inbetween become cells for image display (not illustrated).

To drive the PDP, discharge is started between the address electrode 28and the display electrode 22 or 23 in each cell. Then ultraviolet lightof short wavelength (Xe resonance lines with a wavelength of about 147nm) is generated from glow discharge between the pair of displayelectrodes 22 and 23, and excites the phosphor layers 31-33 to emitlight. This produces an image display.

The above constructed PDP, however, has the following problem.

FIG. 7 is a sectional view of an edge part of the PDP and its vicinity(taken along an address electrode 28). The sealing member 40 made offrit glass is melted and fixed between the back panel glass 27 and thedielectric layer 24, and also melted and fixed between the addresselectrode 28 and the dielectric layer 24 as shown in the drawing. Whenmelting the sealing member 40 between the address electrode 28 and thedielectric layer 24, the address electrode 28 is heated together withthe sealing member 40, which causes Ag particles in the addresselectrode 28 to diffuse and seep into the sealing member 40.

This diffusion of Ag particles cause the address electrode 28 topartially break and its conductivity to drop. This may even result inshortening of a plurality of address electrodes 28. Moreover, theseepage of Ag particles in the sealing member 40 degrades the sealingmember 40 and reduces its sealing performance.

The same problem may occur between the sealing member 40 and the displayelectrode 22 (23). FIG. 8 is a sectional view showing an edge part ofthe PDP and its vicinity (taken along a bus line 221 (231)). The drawingshows the state where Ag particles in the bus line 221 has seeped intothe sealing member 40. This causes the bus line 221 (231) of the displayelectrode 22 (23) to short out or break, resulting in a decrease inperformance of the PDP.

This problem is especially evident with PDPs that have a fine cellstructure such as those for use in high-definition television, i.e.,PDPs that have very narrow bus lines and address electrodes. Animmediate solution is required.

DISCLOSURE OF INVENTION

The present invention was conceived in view of the problem describedabove, and has a primary object of providing a plasma display devicewhich can exhibit favorable display performance even when the plasmadisplay device has a fine cell structure like those for use inhigh-definition television, and a manufacturing method for the plasmadisplay device.

The stated object can be achieved by a plasma display device having afirst plate and a second plate which face each other with a dischargespace in between, and a sealing member which is provided between thefirst and second plates so as to seal the discharge space at outer edgesof the first and second plates, the plasma display device including: aplurality of electrodes which are formed across an inner major surfaceof one of the first and second plates, and an electrode diffusionpreventive layer which is interposed between the sealing member and eachof the plurality of electrodes.

With the provision of the electrode diffusion preventive layer, theelectrode material is kept from diffusing and seeping into the sealingmember, with it being possible to prevent shorting or breaking of theplurality of electrodes. Hence favorable display performance ismaintained while the plasma display device is driven.

The present invention is especially effective if each of the pluralityof electrodes includes Ag.

Here, the electrode diffusion preventive layer may be formed from adielectric material whose softening point is higher than a melting pointof the sealing member temperature at which the sealing member melts.

Here, the electrode diffusion preventive layer may include glass and anoxide filler.

The stated object can also be achieved by a plasma display deviceincluding: a plurality of first electrodes which are formed across amajor surface of a first plate; a first dielectric layer which is formedon the major surface of the first plate on which the plurality of firstelectrodes have been formed, the first plate and a second plate beingset so that the first dielectric layer faces the second plate with adischarge space in between; and a sealing member which is providedbetween the first and second plates so as to seal the discharge space atouter edges of the first and second plates, wherein the first dielectriclayer has a softening point that is higher than a melting point of thesealing member temperature at which the sealing member melts, and thefirst dielectric layer is extended and interposed between the sealingmember and each of the plurality of first electrodes.

Here, the plasma display device may further include: a plurality ofsecond electrodes which are formed across a major surface of the secondplate; and a second dielectric layer which has a softening point higherthan the melting point of the sealing member temperature at which thesealing member melts and is formed on the major surface of the secondplate on which the plurality of second electrodes have been formed,wherein the second dielectric layer is extended and interposed betweenthe sealing member and each of the plurality of second electrodes.

By interposing the first dielectric layer (the second dielectric layer)between the sealing member and the plurality of first electrodes(between the sealing member and the plurality of second electrodes), thesubstantially same effects produced by the provision of the electrodediffusion preventive layer can be attained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of an edge part of a PDP to which the firstembodiment of the invention relates (taken along an address electrode).

FIG. 2 is a sectional view of an edge part of the PDP in the firstembodiment (taken along a display electrode).

FIG. 3 is a top view of a PDP to which the second embodiment of theinvention relates.

FIG. 4 is a sectional view of an edge part of the PDP in the secondembodiment (taken along an address electrode).

FIG. 5 is a partially sectional and perspective view showing aconstruction of a surface discharge AC PDP.

FIG. 6 is a top view of the PDP.

FIG. 7 is a sectional view of an edge part of a conventional PDP (takenalong an address electrode).

FIG. 8 is a sectional view of an edge part of the conventional PDP(taken along a display electrode).

BEST MODE FOR CARRYING OUT THE INVENTION 1. First Embodiment

1-1. Construction of Characterizing Portions of a PDP

An internal construction of a PDP to which the first embodiment of theinvention relates is fundamentally similar to that shown in FIG. 5. Thedifference with the conventional PDP, however, lies in the constructionaround the sealing member 40. As can be seen in a sectional view of apart of the PDP around the sealing member 40 in FIG. 1, in the firstembodiment the sealing member 40 is not in direct contact with the backpanel 26, as an electrode diffusion preventive layer 50 is interposedbetween the sealing member 40 and the back panel glass 27 (and theaddress electrode 28).

As one example, the electrode diffusion preventive layer 50 is formedfrom glass and a filler made of oxides (e.g. Al₂O₃, TiO₂). The softeningpoints (about 560° C.) of these dielectric materials are higher than themelting point temperature at which the sealing member melts (about 360°C.) of the frit glass in the sealing member 40.

The electrode diffusion preventive layer 50 is applied around thedielectric layer 24 so as to assume a thickness of about 10 μm.

1-2. Effects of the Electrode Diffusion Preventive Layer

Conventionally, the front panel 20 and the back panel 26 are sealed withthe sealing member 40 and the address electrodes 28 being in contactwith each other at the edges of the back panel glass 27. The sealing isdone by melting the sealing member 40 in a high-heat oven and thencooling it.

In this sealing process, the address electrode 28 (including Ag andglass) melts to some extent together with the sealing member 40, due tothe heating in the high-heat oven. Since the melting point of the fritglass temperature at which the frit glass melts is lower than themelting point temperature at which the address electrode 28 melts (e.g.around 530° C.) of the address electrode 28, the frit glass melt with alower viscosity than the address electrode 28. Thus, the two differentkinds of materials, namely the sealing member 40 and the addresselectrode 28, are in contact with each other in their melting states.This being so, Ag particles present in the address electrode 28 diffuseand seep into the sealing member 40 which has a lower viscosity than theaddress electrode 28, as shown in FIG. 7.

The inventors of the present application found that such diffusion of Agparticles tends to cause a plurality of address electrodes 28 to shortout. The inventors also found that depending on the extent of diffusionof Ag particles of a particular address electrode 28, the addresselectrode 28 itself may break.

Such problems are particularly evident with PDPs that have a fine cellstructure such as those for use in high-definition television, i.e. PDPsthat have very narrow address electrodes 28. These problems require animmediate solution.

To solve the problems, the electrode diffusion preventive layer 50 isprovided in the PDP in the first embodiment. Which is to say, the frontpanel 20 and the back panel 26 are sealed with the electrode diffusionpreventive layer 50 and the sealing member 40 being interposed inbetween, so as to avoid the sealing member 40 from being in contact withthe address electrode 28. This electrode diffusion preventive layer 50has a softening point of 560° C., which is higher than the melting pointof the sealing member 40 temperature at which the sealing member 40melts.

Accordingly, even when the address electrode 28 and the sealing member40 melt in the sealing process, Ag particles in the address electrode 28will not diffuse and seep into the sealing member 40, since theelectrode diffusion preventive layer 50 is interposed between theaddress electrode 28 and the sealing member 40. Also, the electrodediffusion preventive layer 50 is in a more favorable solid state thanthe sealing member 40 during the sealing process. This effectivelyprevents the Ag particles of the address electrode 28 from seeping intothe sealing member 40.

As a result, the problems such as shorting and electrical break of aplurality of address electrodes 28 can be avoided. This enables the PDPto exhibit favorable display performance.

1-2. Manufacturing Method for the PDP

One example method for manufacturing the PDP of the first embodiment isexplained below.

1-2-a. Manufacture of the Front Panel

A front panel glass 21 is made of soda lime glass and has a thickness ofabout 2.6 mm. As one example, the front panel glass 21 is 600 mm longand 950 mm wide.

A plurality of pairs of display electrodes 22 and 23 are formed on thefront panel glass 21 at a predetermined pitch, so that each electrodeextends along the direction of the width of the front panel glass 21(the direction x). The formation of the display electrodes 22 and 23 canbe performed using the following photo-etching method.

First, a photoresist (e.g. an ultraviolet-curing resist) is applied toone of the major surfaces of the front panel glass 21 so as to assume athickness of about 0.5 μm. A photomask of a predetermined pattern isplaced on top of that, and ultraviolet light is applied. The result issoaked in a developer to wash away parts which have not been cured.After this, a transparent electrode material (ITO) is applied to thegaps of the resist on the front panel glass 21 using CVD. The resist isthen washed away with a cleansing liquid to obtain transparentelectrodes 220 and 230.

Following this, bus lines 221 and 231 with a thickness of about 4 μm areformed on the transparent electrodes 220 and 230, using a metal materialmainly composed of Ag (e.g. DC202 photoimageable Ag conductor producedby E.I. du Pont de Nemours and Company, which has a melting pointtemperature at which the material melts of 580° C.). The formation ofthe bus lines 221 and 231 may be performed using photo-etching or screenprinting. Screen printing is performed as follows. A mesh is attached toa rectangular frame which is larger than the front panel glass 21. Thismesh is pressed against the front panel glass 21, and a paste includingAg is applied to the major surface of the front panel glass 21 throughthe mesh using a squeegee.

This completes the display electrodes 22 and 23.

Next, a lead glass paste is applied to the major surface of the frontpanel glass 21 on which the display electrodes 22 and 23 are arranged,using screening printing. The thickness of the coating is around 15-45μm. The glass paste is then baked to form a dielectric layer 24.

Here, the dielectric layer 24 is 550 mm long and 900 mm wide, and iscentered on the major surface of the front panel glass 21.

A protective layer 25 with a thickness of about 0.3-0.6 μm is formed onthe dielectric layer 24 using evaporation, CVD (chemical-vapordeposition), or the like. Magnesium oxide (MgO) is typically used forthe protective layer 25. However, when partially changing the materialof the protective layer 25, such as when using MgO and alumina (Al₂O₃)separately, the protective layer 25 is formed by patterning that uses ametal mask as appropriate.

This completes the front panel 20.

1-2-b. Manufacture of the Back Panel

A back panel glass 27 is made of soda lime glass and has a thickness ofabout 2.6 mm. As one example, the back panel glass 27 is 650 mm long and900 mm wide, like the front panel glass 21.

A conductor material (with a melting point temperature at which thematerial melts of about 520° C.) including Ag and glass is applied toone of the major surfaces of the back panel glass 27 in stripes at apredetermined pitch using screen printing or the like, so that eachelectrode extends along the direction of the width of the back panelglass 27. The result is baked to form a plurality of address electrodes28 with a thickness of about 5 μm. Here, to keep with the requirementsfor a 40-inch NTSC or VGA television, the distance between the adjacentaddress electrodes 28 is no greater than around 0.4 mm. In thisembodiment, the distance between the address electrodes 28 is 0.3 mm asone example.

The pitch of the address electrodes 28 determined here is equivalent tothe pitch of the barrier ribs 30.

Following this, a lead glass paste is applied to the entire surface ofthe back panel glass 27 on which the address electrodes 28 are arranged,so as to assume a thickness of about 20-30 μm. The result is baked toform a dielectric layer 29.

Next, barrier ribs 30 with a height of about 120 μm are formed in thegaps (about 150 μm) between the adjacent address electrodes 28 on thedielectric layer 29, using the same glass material as the dielectriclayer 29. The barrier ribs 30 can be formed, for example, by repeatedlyscreen-printing a paste which includes the above glass material and thenbaking it. The barrier ribs 30 can also be formed using sandblasting.

Once the barrier ribs 30 have been formed, the phosphor inks of thethree colors of red (R), green (G), and blue (B) are applied one at atime to the side faces of the barrier ribs 30 and the exposed surface ofthe dielectric layer 29 between the barrier ribs 30. The result is driedand baked to form phosphor layers 31-33.

Examples of phosphor materials typically used for PDPs are given below:

-   -   Red phosphor: (Y_(x)Gd_(1-x))BO₃:Eu³⁺    -   Green phosphor: Zn²SiO₄:Mn    -   Blue phosphor: BaMgAl₁₀O₁₇:Eu³⁺        -   (or BaMgAl₁₄O₂₃:Eu³⁺)

A powder with an average particle diameter of about 3 μm may be used foreach phosphor material. Though there are several methods for applyingphosphor ink, this embodiment employs a known meniscus method thatexpels phosphor ink from a fine nozzle while forming a meniscus (across-linking due to surface tension). This method has an advantage ofevenly applying phosphor ink to desired parts. However, it should beobvious that the present invention is not limited to this method. Othermethods such as screen printing are also applicable.

This completes the back panel 26.

Though the front panel glass 21 and the back panel glass 27 are made ofsoda lime glass in this embodiment, this is a mere example of materialthat can be used for the front panel glass 21 and the back panel glass27, which may be formed from other materials.

1-2-c. Manufacture of the Electrode Diffusion Preventive Layer

A glass paste made of lead glass and an oxide filler is applied aroundthe dielectric layer 29 in the back panel 26 (see FIG. 6). The glasspaste is baked at about 560° C. The softening point of this glass pasteis higher than the melting point of the frit glass temperature at whichthe frit glass melts in the sealing member 40 (described later). Thesoftening point of the glass paste is preferably at least 50° C. higherthan the melting point of the sealing member 40 temperature at which thesealing member 40 melts. Also, it was found through experimentation thatthe softening point of the glass paste is preferably 300° C. or above.

This completes the electrode diffusion preventive layer 50.

1-2-d. Sealing Process

A paste of frit glass for the sealing member 40 is applied onto theelectrode diffusion preventive layer 50. As one example, a paste ofPbO—B₂O₃—SiO₂ frit glass with a softening point of 360° C. (ASF2300manufactured by Asahi Glass Co., Ltd.) is applied using screen printing.Other commercially available materials such as ASF2300M and ASF2452(with softening points of 350-360° C.) may instead be used for the fritglass.

Although other commercially available materials may be used for the fritglass as necessary, it is desirable to select a material thateffectively suppresses the occurrence of bubbles and the reaction withelectrodes.

The front panel 20 and the back panel 26 are positioned so that theprotective layer 25 and the barrier ribs 30 face each other, and the twopanels 20 and 26 are sandwiched together so that their longitudinaldirections cross at right angles.

The two panels 20 and 26 are then put in a high-heat oven and undergosintering (at about 450° C. for 0.5 hour).

During this sintering, the address electrode 28 (including Ag and glass)melt to some extent together with the sealing member 40. Here, theviscosity of the melted sealing member 40 is lower than the viscosity ofthe melted address electrode 28. In conventional PDPs, the sealingmember 40 is in direct contact with the address electrode 28. Therefore,Ag particles in the address electrode 28 diffuse and seep into thesealing member 40 due to the difference in viscosity of the sealingmember 40 and address electrode 28, which causes the address electrode28 to break or short out.

In the first embodiment, however, the electrode diffusion preventivelayer 50 whose softening point is higher than the melting point of thesealing member 40 temperature at which the sealing member 40 melts isprovided between the address electrode 28 and the sealing member 40.This keeps Ag particles in the address electrode 28 from diffusing andseeping into the sealing member 40. In other words, the electrodediffusion preventive layer 50 has a higher softening point than thesealing member 40. Accordingly, Ag particles in the address electrode 28are less prone to diffuse and seep into the electrode diffusionpreventive layer 50 than into the sealing member 40. As a result, theproblem of the Ag particles diffusing and seeping into the sealingmember 50 is avoided.

Hence the sealing process can be favorably carried out in thisembodiment.

After the sintering of the front panel 20 and the back panel 26, coolingis performed to secure the sealing member 40.

1-2-e. Completion of the PDP

Following this, the discharge spaces are evacuated to produce a highvacuum (around 1.1×10⁻⁴ Pa), and discharge gas such as an Ne—Xe mixture,an He—Ne—Xe mixture, or an He—Ne—Xe—Ar mixture is introduced into thedischarge spaces at a specified pressure (e.g. 2.7×10⁵ Pa)

It was found through experimentation that the filling gas pressure ispreferably in a range of 800 to 5.3×10⁵ Pa to improve luminousefficiency.

Lastly, drive circuits (not illustrated) for driving the displayelectrodes 22 and 23 and the address electrodes 28 are connected to theedge parts 211, 212, 271, and 272 of the panel glasses 21 and 27, tocomplete the PDP.

1-3. Modifications to the First Embodiment

The above embodiment describes the case where the electrode diffusionpreventive layer 50 is provided between the address electrode 28 and thesealing member 40, but the invention should not be limited to such. Asshown in a sectional view of the edge part 211 and its vicinity in FIG.2, the electrode diffusion preventive layer 50 may be provided betweenthe display electrode 22 (23) (more precisely the bus line 221 (231))and the sealing member 40. In this way, Ag particles in the bus line 221(231) will not diffuse and seep into the sealing member 40, with itbeing possible to prevent the display electrode 22 (23) from breaking orshorting out. As a result, favorable display performance can bedelivered.

Also, the electrode diffusion preventive layer 50 may be provided bothbetween the address electrode 28 and the sealing member 40 and betweenthe bus line 221 (231) and the sealing member 40.

2. Second Embodiment

While the first embodiment uses the electrode diffusion preventive layer50, the second embodiment has a construction in which the edges of thedielectric layer 29 have been extended to serve as the electrodediffusion preventive layer, as shown in a top view of FIG. 3 (in thedrawing, the number of display electrodes 22 and 23 and the number ofaddress electrodes 28 are fewer than in actual PDPs for purposes ofillustration with the electrodes being indicated by solid lines, and thepositions of the sealing member 40 and dielectric layer 24 are alsoindicated by solid lines).

In more detail, the extended part of the dielectric layer 29 isinterposed between the sealing member 40 and each address electrode 28,as shown in a sectional view of the edge part 271 and its vicinity inFIG. 4.

The dielectric layer 29 in this embodiment has a softening point that ishigher than the melting points of the address electrode 28 and sealingmember 40 temperature at which the address electrode 28 and sealingmember 40 melt, and is resistant to reaction with Ag. The dielectriclayer 29 is composed of glass and an oxide filler which are dielectricmaterials. Silicon nitride (SiN) can be used as the oxide filler. Asalternatives, SiO₂ or a combination of SiN and SiO₂ may be used as theoxide filler. Commercially available materials such as YPT061F(PbO—B₂O₃—SiO₂), YPW040 (PbO—B₂O₃—SiO₂), and PLS3244 (PbO—B₂O₃—SiO₂)produced by Asahi Glass Co., Ltd. are also applicable. The dielectriclayer 29 formed from any of these commercially available materials canfavorably avoid the problems such as break and shorting of addresselectrodes 28, thereby delivering excellent effects.

Preferably, the material of the dielectric layer 29 has a softeningpoint which is at least 50° C. higher than the melting points of theaddress electrode 28 and sealing member 40 temperature at which theaddress electrode 28 and sealing member 40 melt. Also, the inventorsfound through experimentation that the diffusion of Ag particles can beprevented if the softening point of the material of the dielectric layer29 is no lower than 300° C.

Through the use of such a dielectric layer 29, the same effects as thefirst embodiment can be obtained. Which is to say, since the dielectriclayer 29 whose softening point is higher than the melting points of theaddress electrode 28 and sealing member 40 temperature at which theaddress electrode 28 and sealing member 40 melt is provided between theaddress electrode 28 and the sealing member 40, Ag particles in theaddress electrode 28 are kept from diffusing and seeping into thesealing member 40 in the sealing process. Hence the problems such asbreak and shorting of address electrodes 28 are avoided. This enablesthe PDP to deliver favorable display performance.

Though the dielectric layer 29 is extended to reach the area displaybelow the sealing member 40 in FIG. 4, the invention should not belimited to such. For instance, the dielectric layer 24 may be extendedto reach the area directly below the sealing member 40. This prevents Agparticles in the bus line 221 (231) of the display electrode 22 (23)from diffusing and seeping into the sealing member 40. Here, thedielectric layer 24 is preferably formed from glass and an oxide filler,as in the case of the dielectric layer 29.

Also, both the dielectric layer 24 and the dielectric layer 29 may beextended.

2-1. Modifications to the Second Embodiment

The second embodiment can be applied to PDPs in which a dielectric layeris provided to only one of the front and back panels.

INDUSTRIAL APPLICABILITY

The present invention can be used for PDPs for use in televisionreceivers or the like, and manufacturing methods for such PDPs.

1. A plasma display device having a first plate and a second plate whichface each other with a discharge space in between, and a sealing memberwhich is provided between the first and second plates so as to seal thedischarge space at edges of the first and second plates, the plasmadisplay device comprising: a plurality of electrodes, each including Ag,which are formed across an inner major surface of one of the first andsecond plates, and an electrode diffusion preventive layer whichincludes glass and an oxide filler is interposed between the sealingmember and each of the plurality of electrodes, wherein the electrodediffusion preventive layer is formed from a dielectric material whosesoftening point is higher than a melting point of the sealing membertemperature at which the sealing member melts.
 2. The plasma displaydevice of claim 1, wherein the softening point of the electrodediffusion preventive layer is at least 50° C. higher than the meltingpoint of the sealing member temperature at which the sealing membermelts.
 3. The plasma display device of claim 1, wherein the softeningpoint of the electrode diffusion preventive layer is no lower than 300°C.
 4. A plasma display device comprising: a plurality of firstelectrodes each including Ag which are formed across a major surface ofa first plate; a first dielectric layer which is formed on the majorsurface of the first plate on which the plurality of first electrodeshave been formed, the first plate and a second plate being set so thatthe first dielectric layer faces the second plate with a discharge spacein between; and a sealing member which is provided between the first andsecond plates so as to seal the discharge space at edges of the firstand second plates, wherein the first dielectric layer includes glass andan oxide filler, has a softening point that is higher than a meltingpoint of the sealing member temperature at which the sealing membermelts, and the first dielectric layer is extended and interposed betweenthe sealing member and each of the plurality of first electrodes.
 5. Theplasma display device of claim 4, wherein the softening point of thefirst dielectric layer is at least 50° C. higher than the melting pointof the sealing member temperature at which the sealing member melts. 6.The plasma display device of claim 4, further comprising: a plurality ofsecond electrodes which are formed across a major surface of the secondplate; and a second dielectric layer which has a softening point higherthan the melting point of the sealing member temperature at which thesealing member melts and is formed on the major surface of the secondplate on which the plurality of second electrodes have been formed,wherein the second dielectric layer is extended and interposed betweenthe sealing member and each of the plurality of second electrodes. 7.The plasma display device of claim 6, wherein each of the plurality ofsecond electrodes includes Ag.
 8. The plasma display device of claim 6,wherein the second dielectric layer includes glass and an oxide filler.9. The plasma display device of claim 8, wherein the oxide fillerincludes at least one of SiN and SiO2.
 10. The plasma display device ofclaim 6, wherein a principal component of the second dielectric layer isa glass material having a softening point of no lower than 300° C. 11.The plasma display device of claim 6, wherein the softening point of thesecond dielectric layer is at least 50° C. higher than the melting pointof the sealing member temperature at which the sealing member melts. 12.A manufacturing method for a plasma display device having a sealingmember forming step for providing a sealing member between a first plateand a second plate which face each other with a discharge space inbetween, so that the discharge space is sealed at edges of the first andsecond plates, the manufacturing method comprising the following stepswhich are performed in the stated order before the sealing memberforming step: an electrode forming step for forming a plurality ofelectrodes including Ag across an inner major surface of one of thefirst and second plates; and an electrode diffusion preventive layerforming step for interposing an electrode diffusion preventive layerincluding glass and an oxide filler between the sealing member and eachof the plurality of electrodes, wherein the electrode diffusionpreventive layer forming step forms the electrode diffusion preventivelayer from a dielectric material whose softening point is higher than amelting point of the sealing member temperature at which the sealingmember melts in the sealing member forming step.
 13. The manufacturingmethod of claim 12, wherein the electrode diffusion preventive layerforming step forms the electrode diffusion preventive layer whosesoftening point is at least 50° C. higher than the melting point of thesealing member temperature at which the sealing member melts in thesealing member forming step.
 14. The manufacturing method of claim 12,wherein the electrode diffusion preventive layer forming step forms theelectrode diffusion preventive layer whose softening point is no lowerthan 300° C.
 15. A manufacturing method for a plasma display devicecomprising: a first electrode forming step for forming a plurality offirst electrode including Ag across a major surface of a first plate; afirst dielectric layer forming step for forming a first dielectric layerincluding glass and an oxide filler on the major surface of the firstplate on which the plurality of first electrodes have been formed; and asealing member forming step for providing a sealing member between thefirst plate and a second plate which are set with the first dielectriclayer facing the second plate with a discharge space in between, so thatthe discharge space is sealed at edges of the first and second plates,wherein in the first dielectric layer forming step, the first dielectriclayer is formed from a material whose softening point is higher than amelting point of the sealing member temperature at which the sealingmember melts in the sealing member forming step, and the firstdielectric layer is extended and interposed between the sealing memberand each of the plurality of first electrodes.
 16. The manufacturingmethod of claim 15, further comprising: a second electrode forming stepfor forming a plurality of second electrodes across a major surface ofthe second plate; and a second dielectric layer forming step for forminga second dielectric layer on the major surface of the second plate onwhich the plurality of second electrodes have been formed, wherein inthe second dielectric layer forming step, the second dielectric layer isformed from a material whose softening point is higher than the meltingpoint of the sealing member temperature at which the sealing membermelts in the sealing member forming step, and the second dielectriclayer is extended and interposed between the sealing member and each ofthe plurality of second electrodes.
 17. The manufacturing method ofclaim 16, wherein the second electrode forming step forms the pluralityof second electrodes using Ag.
 18. The manufacturing method of claim 16,wherein the second dielectric layer forming steps forms the seconddielectric layer from a material that includes glass and an oxidefiller.
 19. A manufacturing method for a plasma display device having asealing member forming step for providing a sealing member between afirst plate and a second plate which face each other with a dischargespace in between, so that the discharge space is sealed at edges of thefirst and second plates, the manufacturing method comprising: anelectrode forming step for forming a plurality of electrodes thatincludes Ag across a major surface of one of the first and secondplates; an electrode diffusion preventive layer forming step forproviding an electrode diffusion preventive layer including glass and anoxide filler onto the major surface of one of the first and secondplates; and a sealing member forming step for providing a sealing memberonto the electrode diffusion preventive layer, setting the first plateand the second plate so that the electrode diffusion preventive layerfaces the second plate with a discharge space in between, and sinteringthe first plate and the second plate so that the discharge space issealed at edges of the first and second plates, wherein the electrodediffusion preventive layer forming step forms the electrode diffusionpreventive layer from a dielectric material whose softening point ishigher than a temperature at which the sealing member melts whilesintering the first plate and the second plate in the sealing memberforming step.
 20. The manufacturing method of claim 19, wherein theelectrode diffusion preventive layer forming step forms the electrodediffusion preventive layer whose softening point is at least 50° C.higher than the temperature at which the first plate and the secondplate are sintered in the sealing member forming step.
 21. Themanufacturing method of claim 19, wherein the electrode diffusionpreventive layer forming step forms the electrode diffusion preventivelayer whose softening point is no lower than 300° C.
 22. A manufacturingmethod for a plasma display device comprising: a first electrode formingstep for forming a plurality of first electrodes that include Ag acrossa major surface of a first plate; a first dielectric layer forming stepfor forming a first dielectric layer including glass and an oxide filleron the major surface of the first plate on which the plurality of firstelectrodes have been formed; and a sealing member forming step forproviding a sealing member onto the first plate or a second plate,setting the first plate and the second plate so that the firstdielectric layer faces the second plate with a discharge space inbetween, and sintering the first plate and the second plate at atemperature so that the discharge space is sealed at edges of the firstand second plates, wherein in the first dielectric layer forming step,the first dielectric layer is formed from a material whose softeningpoint is higher than a temperature at which the sealing member meltswhile sintering the first plate and the second plate in the sealingmember forming step, and the first dielectric layer is extended andinterposed between the sealing member and each of the plurality of firstelectrodes.
 23. The manufacturing method of claim 22, furthercomprising: a second electrode forming step for forming a plurality ofsecond electrodes across a major surface of the second plate; and asecond dielectric layer forming step for forming a second dielectriclayer on the major surface of the second plate on which the plurality ofsecond electrodes have been formed, wherein in the second dielectriclayer forming step, the second dielectric layer is formed from amaterial whose softening point is higher than the temperature at whichthe first plate and the second plate are sintered in the sealing memberforming step, and the second dielectric layer is extended and interposedbetween the sealing member and each of the plurality of secondelectrodes.
 24. The manufacturing method of claim 23, wherein the secondelectrode forming step forms the plurality of second electrodes usingAg.
 25. The manufacturing method of claim 23, wherein the seconddielectric layer forming step forms the second dielectric layer from amaterial that includes glass and an oxide filler.